[MacPorts] #47255: making port:xz optionally independent of other ports

[MacPorts]

#47255: making port:xz optionally independent of other ports
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  Reporter:  rjvbertin@…  |      Owner:  ryandesign@…
      Type:  enhancement  |     Status:  new
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:
Resolution:               |   Keywords:  haspatch
      Port:  xz           |
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Comment (by ryandesign@…):

 I agree that I don't want to add this variant and that I would rather work
 on getting an xz compressor/decompressor bundled with base. The hard work
 for that was already done when we started bundling tcl; I think adding
 more bundled software at this point would be easy. The question is which
 software.

 The official xz has complicated licensing. From the COPYING file, "liblzma
 is in the public domain" and "xz, xzdec, and lzmadec command line tools
 are in the public domain unless GNU getopt_long had to be compiled and
 linked in from the lib directory. The getopt_long code is under GNU
 LGPLv2.1+." We would want to know whether the xz we bundle is public
 domain or LGPL-2.1+. Also, xz and liblzma are not multithreaded, as far as
 I know. We recently added support to MacPorts to use pbzip2, a parallel
 bzip2 implementation, which speeds up compression and decompression; it
 would be undesirable to now lose that speedup by moving to a different
 compression format.

 There are a number of parallel xz implementations, which I think we should
 evaluate. There's [https://jnovy.fedorapeople.org/pxz/ pxz] which I wanted
 to make a port of, but the official source download is
 [https://github.com/jnovy/pxz/issues/21 over 5 years old] and there has
 been no movement on my request to release a new version; also, it's GPL,
 but at least it's not GPL 3.

 There's [https://github.com/vasi/pixz pixz] which is 2-clause BSD
 licensed. It needs xz's liblzma but as per above that's public domain. I
 think I'll try to make a port for this. Its README points to two other
 parallel xz programs, plzip and ChopZip. The author seems to think that
 the indexable files pixz produces are better.

-- 
Ticket URL: <https://trac.macports.org/ticket/47255#comment:4>
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